Performance of cryopreserved pre-embryos obtained in in vitro fertilization cycles with or without a gonadotropin-releasing hormone agonist

Impact of serum estradiol levels on the implantation rate of cleavage stage cryopreserved-thawed embryos transferred in programmed cycles with exogenous hormonal replacement

PURPOSE

To investigate the impact of late follicular phase serum estradiol (E2) levels on implantation and pregnancy outcomes of cleavage stage cryopreserved/thawed embryos transferred in programmed cycles with exogenous hormonal replacement.

METHODS

Retrospective cohort analysis of IVF patients with transfer of cryopreserved-thawed day-3 embryos in E2 and progesterone (P4) supplemented cycles (n = 208 cycles).

MAIN OUTCOME MEASURES

implantation and pregnancy rates according to late follicular phase serum E2 levels and early secretory phase E2/P4 ratios.

RESULTS

Logistic regression performed for embryo implantation and for pregnancy outcome in relation to E2 (day 15), P4 (day 15 and 16), before (crude analysis) and after adjustment (adjusted analysis) for baseline characteristics (including age, BMI, serum basal cycle day 3 FSH levels, embryo quality, endometrial lining thickness) showed no significant association. Similarly, ROC analysis showed no impact of cycle day 16 E2/P4 ratio.

CONCLUSIONS

Neither late follicular phase serum E2 nor the early E2/P4 ratio were able to predict implantation or pregnancy outcome of day-3 cryopreserved-thawed embryos transferred in artificially programmed cycles.

Postthaw blastomere survival is predictive of the success of frozen?Thawed embryo transfer cycles

OBJECTIVE

To investigate the predictors of postthaw blastomere survival and the relationship of blastomere survival to the outcome of frozen-thawed embryo transfer (FET) cycles.

DESIGN

Retrospective study.

SETTING

An IVF unit in a tertiary care facility.

PATIENT(S)

Infertile women undergoing FET cycles with embryos cryopreserved on day 3 postinsemination.

INTERVENTION(S)

FET cycles.

MAIN OUTCOME MEASURE(S)

Embryo survival postthaw, pregnancy (PR), clinical pregnancy, and implantation rates.

RESULT(S)

A significant impact of postthaw blastomere survival on the outcome of FET cycles was noted. The thawed embryos in the low survival tertile resulted in significantly impaired implantation rate, clinical pregnancy rate, and PR compared to embryos in the high survival tertile. An inverse association was noted between serum P levels on the day of hCG administration and postthaw blastomere survival.

CONCLUSION(S)

We have demonstrated that postthaw blastomere survival is predictive of success of FET cycles. The relationship of poor postthaw embryo survival in the setting of elevated P is novel and not hitherto described.

Randomized controlled study of human zona pellucida dissection using the zona infrared laser optical system: evaluation of blastomere damage, embryo development, and subsequent hatching

OBJECTIVE

To assess the effect of laser hatching on human embryo damage and subsequent development using the Zona Infrared Laser Optical System (ZILOS).

DESIGN

Randomized controlled study.

SETTING

Tertiary care fertility clinic.

PATIENT(S)

One hundred fourteen donated and discarded frozen human embryos.

INTERVENTION(S)

Embryos were thawed, cultured with cleavage and morphology evaluated periodically, and randomized into control, partial hatching, or complete hatching groups. The laser hatching procedure was performed by ZILOS. Zona thickness and embryo diameter were recorded. Complete hatching involved the production of a full-thickness defect in the zona and partial hatching, a defect in the outer half of the zona. No laser treatment was administered to the control group.

MAIN OUTCOME MEASURE(S)

Blastocyst development and completion of hatching process.

RESULT(S)

No significant difference was noted between the three study groups for their baseline characteristics. There was no significant difference in blastocyst development among the three groups. However, the complete hatching group showed a significant increase in hatching compared to the control group.

CONCLUSION(S)

Complete laser hatching of human embryos using the ZILOS does not have an adverse effect on subsequent development and increases the rate of completion of hatching.

Frozen pronuclear oocytes: advantages for the patient

Since the first reported pregnancy in a human being after a frozen/thawed eight cell stage preembryo, cryopreservation of preembryos has been integrated as an important element of assisted reproductive technologies (ART). The cryopreservation technique has brought several advantages to ART. It allows the transfer of a limited number of embryos in the collection cycle, thereby reducing the risk of multiple pregnancies, and the patients have a reservoir of excess embryos for additional transfers. This maximises the number of embryo transfers per oocyte retrieval, while at the same time increasing the cumulative pregnancy rate from a given treatment cycle. Also, the ability to freeze all the embryos obtained and transfer at a subsequent cycle is useful in the avoidance of hyperstimulation syndrome, or when factors that may jeopardize implantation are apparent. Freezing of oocytes in a pronuclear stage has a valuable role in the management of infertility. Supernumerary zygotes can be cryopreserved safely for future transfer, avoiding additional inconvenience for the patients. The freezing thawing technique does not have any adverse effects on oocytes fertilized microsurgically. Pronuclear stage oocytes eventually survive the cryopreservation procedure better, yielding after culture cleaved embryos appropriate for transfer, which could increase the implantation rate. We believe that the cryopreservation of cleaved embryos, which is problematic, can be safely replaced by this procedure. This is not only an advantage for society as a whole, but also for the people involved in the process, as there should be no ethical or moral conflict for the patients or for the laboratory staff about discarding this material.

Impact of different clinical variables on pregnancy outcome following embryo cryopreservation

In our program's 13 years of experience, more than 9000 embryos have been cryopreserved in gonadotropin-stimulated IVF cycles. Over 1500 thaw and transfer cycles have yielded a pregnancy rate of approximately 25%. Different ovarian stimulation regimens (various preparations of FSH. alone or in combination with hMG, with or without concomitant use of a GnRH agonist) did not influence embryo survival or pregnancy rate. Likewise, the application of oocyte/embryo micromanipulation techniques for assisted fertilization (ICSI for male infertility) or assisted hatching (performed selectively) did not have an impact on pregnancy results. Survival and transfer rates of embryos cryopreserved at pronuclear or cleaving stage did not differ significantly. However, implantation and pregnancy rates were higher with pronuclear embryo freezing (day-2 transfers) when compared to embryos frozen at the cleavage stage (day-3 transfers). This may be the result of patient selection and transfer policies. Similar implantation and pregnancy results were achieved in natural and estrogen progesterone supplemented transfer cycles. Initial experience with pronuclear freezing followed by transfer at the blastocyst stage appears to offer a very successful alternative for selected patients.

The effect of gonadotropin-releasing hormone agonist on embryo quality and pregnancy rate following cryopreservation

OBJECTIVE

To examine the effect of GnRH analogue (GnRH-a) on the quality of frozen-thawed embryos and the pregnancy rate (PR) resulting from transfer.

DESIGN

A retrospective study of two groups of women undergoing transfers of frozen-thawed embryos. In group 1 ovulation induction with hMG was begun after hypophyseal desensitization with GnRH-a for 2 weeks. In group 2 ovulation was induced with hMG only. The freezing and thawing techniques were identical for both groups.

SETTING

In vitro fertilization unit at a university hospital.

PATIENTS

The study group (group 1) included 108 women who underwent 137 transfer cycles of frozen-thawed embryos, and the control group (group 2) included 44 women in 51 cycles of thawed ETs.

INTERVENTIONS

Ovum pick-up and ET techniques were the same for both groups. Methods of embryo freezing and thawing were identical, as were the morphological criteria for grading the embryos.

RESULTS

The morphology of embryos was similar in both groups, as was the number of embryos that had at least 50% intact blastomeres (83% +/- 23% and 78% +/- 30% for group 1 and group 2, respectively). The PR (16 of 137 [11.7%] and 6 of 51 [11.8%], respectively) as well as the abortion rate (30%) were similar for both groups.

CONCLUSIONS

The use of GnRH-a does not affect the quality of embryos nor the pregnancy outcome. Because the yield of frozen embryos per ovum pick-up is higher in cycles stimulated by GnRH-a/hMG, the PR per pick-up cycle is thus anticipated to be higher.

Appraisal of in vitro fertilization

In-vitro fertilization and embryo transfer techniques are now used all over the world (53 countries). The results of 492 of all world units were collected from national surveys and registries of different countries. Since 1985, more than 53,635 women were treated and 34,316 babies were born by 224,473 treatment cycles, followed by more than 160,518 transfer cycles. Only about 65%-75% of all resulting pregnancies attained live births. The remainder ended with spontaneous abortions (26%), or ectopic pregnancies (5.54%). The multiple pregnancy rate (22%) was higher than the normal population and contributed to higher rates of preterm deliveries and perinatal mortality. No increased incidence of chromosomal aberrations and malformations were noted during the years (2.25%). Success rates did not improve significantly within the 5-year period surveyed, in most parts of the world. The indications for treatment were broadened during the years and the procedure became a final step for diagnosis and treatment of unexplained infertility. We conclude that IVF/ET is not an empirical treatment anymore and is a relatively safe procedure, although it should be used only when properly indicated. Male infertility and infertility of unexplained origin may be accepted indications for IVF/ET. More research and centralization of treatment in fewer but large units should be established in order to improve success rates and lower the cost per live birth child. Quality control by professional or public associations should be regulated.

A fast and efficient method for simultaneous X and Y in situ hybridization of human blastomeres

PURPOSE

To use a 6-hr fluorescence in situ hybridization (FISH) procedure involving fluorochrome-labeled probes to determine the gender of blastomeres from arrested biopsied human embryos.

RESULTS

Simultaneous detection of X and Y chromosomes was performed on 68 blastomeres with this technique. The FISH efficiency for gender determination was 95.5% (65/68). In addition, rehybridization with chromosome 8-specific probes was performed to determine the ploidy of blastomeres with more than two sex chromosomes.

CONCLUSION

This technique offers an alternative to polymerase chain reaction for the preimplantation diagnosis of X-linked diseases and can also be used for ploidy assessment.